Most internal combustion engines require a cooling circuit (4)having a coolant pump, radiator (6)and passageways which circulate a coolant from the radiator through the engine block to cool the engine block and the moving components in the engine block. Lubricants, typically a synthetic or mineral-based oil, circulate through the lubrication system (7)to lubricate the relatively moving surfaces in the engine to counteract friction, reduce wear and reduce operating temperatures.
However, excessive heat generated in the operation of the engine may cause the oil to degrade and break down losing its lubricating ability. When motor oils break down, they oxidize, thermally degrade and lose viscosity due to shear forces. As a result, many internal combustion engines, particularly high speed diesel engines and high performance combustion ignition engines, utilize engine block mounted oil coolers. Oil from the engine is passed through a cooler which operates as a heat exchanger with heat exchanger fluid, usually water and glycol, being provided from the engine cooling system from either the radiator or the engine block.
However, since the opening temperature of the thermostat in cooling systems of most internal combustion engines is approximately in the range of 180° to 200° Fahrenheit, an oil cooler utilizing engine coolant as the heat exchanger fluid is limited in its ability to cool the engine oil. By the operation of the cooling system thermostat in many engines, an oil temperature of approximately 200° to 220° F. is maintained so that the oil effectively lubricates and does not break down or degrade. Further, a low oil temperature is preferred because the oil, in addition to being a lubricant, also serves to cool the internal combustion engine components.
In a coolant to oil cooler system, the engine oil temperature is dependent upon the coolant supply. In the event of even a minor coolant loss, the engine may be damaged as the engine will incur the cooling loss provided both by the coolant and the engine oil.
Accordingly, there exists a need for an improved coolant to oil cooler system for IC engines which obviates the deficiencies set forth above.